Yesterday, during the opening hours of the D6 conference, Walt Mossberg and Kara Swisher jointly interviewed Steve Ballmer and Bill Gates. While the interview dealt mostly with the past, Yahoo, and a bit of Vista, by far the most interesting part was the first ever public appearance of Vista's successor: Windows 7. Earlier today, the team behind D6 posted a video of the demonstration, which was conducted by Microsoft's Julie Larson-Green. From a graphical user interface point of view, there were some interesting things in there.

The video shows Larson-Green talking us through the various touch features while answering questions from Mossberg and Swisher.

Let me give you a little history on Julie Larson-Green first. She joined Microsoft back in 1993, and throughout her career at the company she focused on user interface design. Her most important responsibility was the user interface design of Office XP, Office 2003, and most recently, Office 2007. Larson-Green led the massive interface redesign of Office 2007, a bold redesign that led to a completely new and - yes - innovative user interface. She was brought onboard the Windows 7 GUI team almost a year ago.

The demonstration obviously focused on the various multitouch features built right into Windows 7 - they will be available system-wide. Larson-Green called it an "evolution of Surface", and they're of course working together with the Surface team itself. The multitouch features require a digitiser built into the display, which is already shipping on various displays today. So obviously, you're going to need a new monitor.

To me, it seemed as if Larson-Green and the rest of the GUI team realise fully well that multitouch is not an answer to everything, but that it is "much faster to do certain tasks". As Larson-Green explained: "Use touch when it makes sense, use the mouse when it makes sense, use the keyboard when it makes sense." I believe it is indeed wise not to focus all efforts on multitouch as if it is the only sensible input method, but rather see it as an additional input method, that make sense for certain tasks. Larson-Green confirmed Microsoft is working on adding gestures for things like window management.

The applications that were part of the demonstration will not necessarily be part of Windows 7; they are applications written to demonstrate what can be done with the multitouch features in Windows 7. Interestingly, the Concierge application made use of circular menus, a user interface element frequently appearing in mockups lately. As we know, circular menus are potentially easier to use thanks to - dead horse alert - Fitts' Law.

The final interesting part was the rather odd-looking taskbar - assuming it even was a taskbar. The bar was twice as high as an ordinary taskbar, and lacked text, using what looked like icons or thumbnails instead. It reminded me of the RISC OS icon bar, mostly. Apparently, Larson-Green was not at liberty to discuss it, because when Mossberg asked her about it, she replied: "It's something we're working on for Windows 7 and I'm not supposed to talk about right now, today..."

While all we received was a small glimpse, I'm excited about everything that's going on behind the scenes. Larson-Green and Steven Sinofsky have delivered a truly innovative product with Office 2007, and as a GUI enthusiast, I'm excited to see them working on the Windows interface in quite a - for Microsoft - secretive manner. Some people are extremely cynical, and that's fine - I'm more of an optimist and await more information from Redmond.